Short answerOpenAI's file search is a hosted tool in the Responses API that retrieves from files you uploaded to a vector store using semantic and keyword search. It supports file types including PDF, DOCX, PPTX, TXT, MD, JSON and HTML.
The flow
- Create a vector store.
- Upload your files with the Files API and add them to the store.
- Pass the vector store ID in the file_search tool on your Responses API call.
OpenAI says the Responses API is recommended for new projects and that the Assistants API was sunset on August 26, 2026; see rebuilding with the OpenAI API. Pricing for storage and calls is on OpenAI's pricing page, not the guide.
When to use it
It saves you from building your own retrieval if you are already building on OpenAI. Otherwise see how retrieval works and moving a knowledge base.
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Sources
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